Stabilising Copper: A Light-Driven Leap in CO2 Conversion

Converting carbon dioxide (CO2) into useful chemicals is a crucial goal for sustainable science, and the reverse water-gas shift (RWGS) reaction is a key method for turning CO2 into carbon monoxide (CO), a building block for fuels. Copper-based catalysts are promising for this task, but they suffer from a persistent flaw: under the intense heat required, copper atoms tend to migrate and clump together—a process called sintering—which permanently deactivates the catalyst.

In a significant advance, researchers have developed an 'anti-sintering' solution using a material derived from copper-nickel-magnesium-aluminium layered double hydroxides. The team successfully anchored ultrafine copper-nickel nanoparticles using hydroxyl groups—oxygen-hydrogen pairs that bond tightly to the metal surface. The addition of nickel proved vital; it not only helps lock the copper in place but also enhances the 'plasmonic effect,' allowing the catalyst to absorb light energy efficiently to drive the chemical reaction.

The performance of this new catalyst, named Cu3Ni-MA, is remarkable. It converts CO2 at a rate 3.5 times faster than standard thermal methods, achieving 98 per cent selectivity for carbon monoxide. Most notably, the material is incredibly robust. Throughout 30 days of intermittent start-stop cycles and 280 hours of continuous testing, it retained over 99 per cent of its original activity. This stability suggests a viable new path for designing long-lasting photothermal systems.